I use ubuntu 11.10 and defcon 1.43. Since I begun to play this game I never had the possibility to change the speed with "1" "2" "3" "4" keys ... when i'm in chat, keys "1" and "5" also don't work.
Could someone give help to fix that ?
What other information should I give about my keymap (french, azerty) or other things ?

French keyboards are weird; their number row sends special characters and not the numbers. So when DEFCON checks whether the key 1 is pressed, it never gets 'yes' as answer. And since raw keypresses are checked, not characters, holding shift doesn't help. You can try switching your keyboard layout, but for said keypress checks, SDL seems to always reference your default layout.